802.11 is a set of IEEEstandards that govern wireless networking transmission methods. They are commonly used today in their 802.11a, 802.11b, 802.11g, and 802.11n versions to provide wireless connectivity in the home, office and some commercial establishments.

802.11s extends the IEEE 802.11 MAC standard by defining an architecture and protocol that support both broadcast/multicast and unicast delivery using "radio-aware metrics over self-configuring multi-hop topologies."

A mesh often consists of many small nodes. When mobile users or heavy loads are concerned, there will often be a handoff from one base station to another, and not only from 802.11 but from other (GSM, Bluetooth, PCS and other cordless phone) networks. Accordingly IEEE 802.21, which specifies this handoff between nodes both obeying 802.11s and otherwise, may be required. This is especially likely if a longer-range lower-bandwidth service is deployed to minimize mesh dead zones, e.g. GSM routing based on OpenBTS.

Mesh networking often involves network access by previously unknown parties, especially when a transient visitor population is being served. Thus the accompanying IEEE 802.11u standard will be required by most mesh networks to authenticate these users without pre-registration or any prior offline communication. Pre-standard captive portal approaches are also common. See the more detailed description below of mesh security.

802.11s started as a Study Group of IEEE 802.11 in September 2003. It became a Task Group in July 2004. A call for proposals was issued in May 2005, which resulted in the submission of 15 proposals submitted to a vote in July 2005. After a series of eliminations and mergers, the proposals dwindled to two (the "SEE-Mesh" and "Wi-Mesh" proposals), which became a joint proposal in January 2006. This merged proposal was accepted as draft D0.01 after a unanimous confirmation vote in March 2006.

The draft evolved through informal comment resolution until it was submitted for a Letter Ballot in November 2006 as Draft D1.00. Draft D2.00 was submitted in March 2008 which failed with only 61% approval. A year was spent clarifying and pruning until Draft D3.00 was created which reached WG approval with 79% in March 2009.

The Task Groups stated goal for the May 2009 802.11 meeting is to start resolving comments from its new Letter Ballot.

In June 2011 the fifth recirculation Sponsor Ballot, on TGs Draft 12.0, was closed. The Draft met with 97.2% approval rate.[2]

A mesh architectures allowing otherwise out-of-range nodes 1–4 to still connect to the Internet

Mesh STAs are individual devices using mesh services to communicate with other devices in the network. They can also collocate with 802.11 Access Points (APs) and provide access to the mesh network to 802.11 stations (STAs), which have broad market availability. Also, mesh STAs can collocate with an 802.11 portal that implements the role of a gateway and provides access to one or more non-802.11 networks. In both cases, 802.11s provides a proxy mechanism to provide addressing support for non-mesh 802 devices, allowing for end-points to be cognizant of external addresses.

802.11s also includes mechanisms to provide deterministic network access, a framework for congestion control and power save.

There are no defined roles in a mesh — no clients and servers, no initiators and responders. Security protocols used in a mesh must, therefore, be true peer-to-peer protocols where either side can initiate to the other or both sides can initiate simultaneously.

When peers discover each other (and security is enabled) they take part in an SAE exchange. If SAE completes successfully, each peer knows the other party possesses the mesh password and, as a by-product of the SAE exchange, the two peers establish a cryptographically strong key. This key is used with the "Authenticated Mesh Peering Exchange" (AMPE) to establish a secure peering and derive a session key to protect mesh traffic, including routing traffic.

Clients wishing simply to send and receive packets without routing them for others can use simpler approaches such as 802.11u authentication which avoid pre-authentication. This is not part of the specification of the mesh network itself.

The One Laptop per Child[5] project uses the 802.11s draft standard for its OLPC XO laptop and OLPC XS school server networking. Mesh networking is considered important for classroom applications involving collaboration.

A reference implementation of the 802.11s draft is available as part of the mac80211 layer in the Linux kernel, starting with version 2.6.26.[6] The Linux community, with its many diverse distributions, provides a heterogenous testing ground for protocols like Hybrid Wireless Mesh Protocol.[7]OpenWRT, a Linux distribution for routers, supports mesh networking.[8]·[9]